Intervertebral spinal implant and method

ABSTRACT

A spinal implant is provided. The spinal implant includes a body extending between a proximal end and a distal end. The proximal end defines a notch configured for disposal of a first vertebra. The distal end includes a protrusion configured for disposal in a second vertebra. The proximal and distal ends are movable relative to one another between an unexpanded position in which the spinal implant is inserted between lamina and an expanded position in which the spinal implant is disposed between the lamina.

BACKGROUND

The rapid and effective repair of bone defects caused by injury,disease, wounds, or surgery is a goal of orthopedic surgery. Toward thisend, a number of bone implants have been used or proposed for use in therepair of bone defects including spinal stenosis. The biological,physical, and mechanical properties of the bone implants are among themajor factors influencing their suitability and performance in variousorthopedic applications.

Spinal stenosis is a narrowing of the spinal canal, which can lead to animpingement on the spinal cord and various nerves resulting in symptomsof moderate to extreme pain. Bone implants are used to alleviatesymptoms associated with spinal stenosis. Bone implants are also used torepair bone that has been damaged by disease, trauma, or surgery. Insome types of spinal fusion, for example, bone implants are used toreplace the cushioning disc material between the vertebrae or to repaira degenerative facet joint.

During certain spinal corrective procedures, such as for example,alleviating spinal stenosis pain and/or a spinal fusion procedure, boneimplants are positioned in an interspinous process space. Theinterspinous process bone implants attempt to lessen pain caused byspinal stenosis by redirecting pressure away from the foramina.Interspinous process bone implants can also be used to facilitate boneremodeling and new bone growth, and integration of the bone implant(e.g., allograft) into host bone. However, interspinous process implantscarry several inherent drawbacks. Exemplary disadvantages ofinterspinous process bone implants include difficulty mechanicallyfixing the implant to the spinous processes; erosion of adjacent bone;and fracture of the spinous process due to the relatively thin and weaknature of the spinous processes.

The present disclosure offers several advantages over interspinousprocess implants to lessen pain caused by spinal stenosis and/ormaintain an intervertebral space during fusion of adjacent vertebrae.

SUMMARY

The present disclosure includes a spinal implant configured forengagement with lamina bone, which is much closer to a neutral axis ofthe spine and has greater strength and rigidity than spinous processes.The spinal implant is expandable to a selected length to apply adistracting force on the lamina to reduce the amount of soft tissue thatprotrudes into the spinal canal and foramen, which can be a cause of thepain associated with spinal stenosis.

In some embodiments, the spinal implant of the present disclosure allowsload to be transferred away from the spinous process to theintervertebral foramen and/or lamina. This reduces the risk of fractureof the spinous process, and bone resorption problems resulting fromspinous process fracture.

In one embodiment, there is a spinal implant, comprising: a bodyextending between a proximal end and a distal end, the proximal enddefining a notch or protrusion configured for disposal in a firstvertebra, the distal end comprising a protrusion or protrusionconfigured for disposal in a second vertebra, wherein the proximal anddistal ends of the body are movable relative to one another between anunexpanded position in which the spinal implant is configured to beinserted between lamina and an expanded position in which the spinalimplant is configured to be disposed between the lamina.

In one embodiment, in accordance with the principles of the presentdisclosure, a spinal implant is provided. The spinal implant includes abody extending between a proximal end and a distal end. The proximal enddefines a notch configured for disposal of a first vertebra. The distalend includes a protrusion configured for disposal in a second vertebra.The proximal and distal ends are movable relative to one another betweenan unexpanded position in which the spinal implant is inserted betweenlamina and an expanded position in which the spinal implant is disposedbetween the lamina.

In one embodiment, a spinal implant is provided. The spinal implantincludes a body extending between a proximal end and a distal end. Theproximal end defines a notch configured for disposal of a firstvertebra. The distal end includes a protrusion configured for disposalin a second vertebra. The body includes a jacking member configured forengagement with a driver. The proximal and distal ends are movablerelative to one another via the jacking member between an unexpandedposition in which the spinal implant is inserted between lamina and anexpanded position in which the spinal implant is disposed between thelamina.

In one embodiment, a method for treating a spine disorder is provided.The method includes providing a spinal implant comprising a bodyextending between a proximal end and a distal end. The proximal enddefines a notch configured for disposal of a first vertebra. The distalend includes a protrusion configured for disposal in a second vertebra.The proximal and distal ends are movable relative to one another betweenan unexpanded position and an expanded position. A cavity is formed inthe second vertebra. The protrusion is disposed in the cavity. The bodyis rotated relative to the second vertebra to position the firstvertebra in the notch.

In one embodiment, there is a spinal implant, comprising: a bodyextending between a proximal end and a distal end, the proximal endconfigured for disposal in a first vertebra, the distal end configuredfor disposal in a second vertebra, wherein the proximal and distal endsare movable relative to one another between an unexpanded position inwhich the spinal implant is configured to be inserted between lamina andan expanded position in which the spinal implant is configured to bedisposed between the lamina so as to allow elasticity during motion.

Additional features and advantages of various embodiments will be setforth in part in the description that follows, and in part will beapparent from the description, or may be learned by practice of variousembodiments. The objectives and other advantages of various embodimentswill be realized and attained by means of the elements and combinationsparticularly pointed out in the description and appended claims.

BRIEF DESCRIPTION OF THE FIGURES

In part, other aspects, features, benefits and advantages of theembodiments will be apparent with regard to the following description,appended claims and accompanying drawings where:

FIG. 1 illustrates a perspective view of one embodiment of a spinalimplant in accordance with the principles of the present disclosure.

FIG. 2 illustrates a top view, in cross section, of an embodiment of thespinal implant shown in FIG. 1.

FIG. 2A illustrates a top view, in cross section, of an embodiment ofthe spinal implant shown in FIG. 1.

FIG. 3 illustrates a perspective view, in part cross section, of anembodiment of the spinal implant shown in FIG. 1.

FIG. 3A illustrates a perspective view, of an embodiment of the spinalimplant shown in FIG. 1.

FIG. 4 illustrates a perspective view of the spinal implant shown inFIG. 1 being inserted between vertebrae using a guidewire.

FIG. 5 illustrates a side view of an embodiment of the spinal implantshown in FIG. 1 disposed between vertebrae.

FIG. 6 illustrates a cross sectional view of an embodiment of the spinalimplant shown in FIG. 1, disposed between vertebrae and with animplantation tool.

It is to be understood that the figures are not drawn to scale. Further,the relation between objects in a figure may not be to scale, and may infact have a reverse relationship as to size. The figures are intended tobring understanding and clarity to the structure of each object shown,and thus, some features may be exaggerated in order to illustrate aspecific feature of a structure.

DETAILED DESCRIPTION

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities of ingredients,percentages or proportions of materials, reaction conditions, and othernumerical values used in the specification and claims, are to beunderstood as being modified in all instances by the term “about.”Accordingly, unless indicated to the contrary, the numerical parametersset forth in the following specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the present invention. At the very least, andnot as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Moreover, all ranges disclosed hereinare to be understood to encompass any and all subranges subsumedtherein. For example, a range of “1 to 10” includes any and allsubranges between (and including) the minimum value of 1 and the maximumvalue of 10, that is, any and all subranges having a minimum value ofequal to or greater than 1 and a maximum value of equal to or less than10, e.g., 5.5 to 10.

It is noted that, as used in this specification and the appended claims,the singular forms “a,” “an,” and “the,” include plural referents unlessexpressly and unequivocally limited to one referent. Thus, for example,reference to “a spinal implant” includes one, two, three or more spinalimplants.

Reference will now be made in detail to certain embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings. While the present disclosure will be described inconjunction with the illustrated embodiments, it will be understood thatthey are not intended to limit the disclosure to those embodiments. Onthe contrary, the present disclosure is intended to cover allalternatives, modifications, and equivalents, which may be includedwithin the invention as defined by the appended claims.

The headings below are not meant to limit the disclosure in any way;embodiments under any one heading may be used in conjunction withembodiments under any other heading.

In one embodiment, a system for correcting a spinal abnormality, suchas, for example, spinal stenosis, is provided. The system includes aninterlaminar distraction implant. In one embodiment, the implantincludes an elastomeric or spring loaded member for lengthening theimplant. In one embodiment, the implant includes an internal mechanicalmechanism that lengthens the implant via a pre-tension mechanism. In oneembodiment, the implant includes an expanding mechanism. In oneembodiment, the implant is flexible. In one embodiment, the implant hasa rigid structure.

In some embodiments, the spinal implant of the present disclosure allowsload to be transferred away from the spinous process to theintervertebral foramen and/or lamina. This reduces the risk of fractureof the spinous process, and bone resorption problems resulting fromspinous process fracture.

In one embodiment, the implant is inserted in a minimally invasivelyprocedure. In some embodiments, the implant reduces spinal stenosispain. The implant can be directly anchored into lamina bone and closerto a neutral axis of a spine. In some embodiments, the implant isdistracted to a selected length while being anchored between lamina toreduce the amount of soft tissue that protrudes into a spinal canal andforamen, which is a cause of pain associated with spinal stenosis.

In one embodiment, a method of employing the disclosed spinal implant isprovided. The implant is inserted between lamina in the interlaminarspace. In one embodiment, the method includes inserting an elongatedmember such as a guidewire, rod, or pin such as, for example, aSteinmann pin into a superior lamina. In one embodiment, the Steinmannpin is inserted using fluoroscopic imaging. A small hole is drilled orreamed into the superior lamina, which is sized and dimensioned toreceive a docking tip of the implant. The implant is guided along theSteinmann pin such that the docking tip is disposed in the hole. In oneembodiment, an instrument, such as, for example, a gauge instrument isinserted through the skin of a patient directly above the implant intoengagement with a port of the implant. The gauge instrument ismanipulated to move the implant into a position between adjacent lamina.The gauge instrument is rotated within the port to actuate the internalmechanical mechanism, axially spacing the implant and anchoring theimplant between the lamina. The axial displacement of the implantapplies a distracting force on the lamina to reduce soft tissue stenosisin the spinal canal and foramen.

Spinal Implant

Referring to FIGS. 1-6, FIG. 1 illustrates a perspective view of anembodiment of a spinal implant, such as, for example, a spacer 10 isillustrated. In this illustrated embodiment, spacer 10 comprises a body12 configured for maintaining a space between vertebral tissue, such as,for example, adjacent lamina of a vertebrae V (in FIG. 4). Body 12 has abullet-shaped configuration. In some embodiments, body 12 is variouslyconfigured, such as, for example, round, oval, oblong, square,triangular, rectangular, irregular, uniform, non-uniform, consistent,and/or variable.

Body 12 extends between a proximal end 14 and a distal end 16 defining alongitudinal axis A1 therebetween. Body 12 tapers from proximal end 14to distal end 16. In some embodiments, body 12 has a uniform width alongits length, which is defined between ends 14, 16. Body 12 is cannulatedalong its length such that an elongated element 20, such as, forexample, a Steinmann pin or guidewire can be positioned therein.

Proximal end 14 includes an inner surface defining a notch 18 configuredfor disposal of a first vertebra, such as, for example, an inferiorlamina L1. Notch 18 has a V-shaped configuration. In some embodiments,notch 18 is variously configured, such as, for example, U-shaped,parabolic-shaped, oval, oblong, triangular, arcuate, square, polygonal,irregular, uniform, non-uniform, offset, staggered, undulating, arcuate,variable and/or tapered. In some embodiments, the notch can be instead aprojection (not shown).

Distal end 16 includes a protrusion, such as, for example, a taperedelement 22 configured for disposal in a second vertebra, such as, forexample, a superior lamina L2, adjacent inferior lamina L1. Taperedelement 22 includes a roughened outer surface that adheres to tissue,such as, for example, bone tissue. In some embodiments, the outersurface has alternate configurations, such as, for example, planar,undulating, porous, semi-porous, dimpled, polished and/or textured.Tapered element 22 extends between a proximal end 24 and a distal tip 26defining a cone-shaped configuration therebetween. Proximal end 24 has adiameter substantially equal to one-half of a diameter of proximal end14 of body 12. Distal tip 26 has a rounded configuration. In oneembodiment, distal tip 26 is pointed for penetrating engagement withtissue, such as, for example, spinal tissue. In some embodiments, theprotrusion can be instead a recess (not shown).

Proximal and distal ends 14, 16 are movable, such as, for example,axially translatable, relative to one another between an unexpandedposition and an expanded position. In the unexpanded position, body 12can be inserted between lamina L1, L2. Upon placement of body 12 betweenlamina L1, L2, ends 14, 16 are axially spaced to the expanded positionto apply a tensile force on lamina L1, L2, lessening impingement onnerves and the spinal cord by the foramen and the spinal canal. Body 12includes an expandable intermediate portion 28 disposed between ends 14,16. Intermediate portion 28 includes a biasing member, such as, forexample, a spring. Spring resiliently biases body 12 to the expandedposition.

Proximal end 14 includes a mating part, such as, for example, a femalemating part 30. Distal end 16 includes a mating part, such as, forexample, a male mating part 32. Mating parts 30, 32 are detachablyengagable with one another in the unexpanded position such that proximaland distal ends 14, 16 are in a provisionally locked orientationrelative to one another in the unexpanded position. To move body 12 tothe expanded position, ends 14, 16 are relatively rotated to disengagemating parts 30, 32 such that intermediate portion 28 axially spacesends 14, 16 from one another. In one embodiment, mating parts 30, 32include hook elements. In some embodiments, mating parts 30, 32 includealternative configurations, such as, for example, nails, serrated,textured, staggered, uneven, undulating, smooth, barbs and/or raisedelements to facilitate detachable engagement with one another.

Body 12 comprises at least one of stainless steel alloys, commerciallypure titanium, titanium alloys, Grade 5 titanium, cobalt-chrome alloys,stainless steel alloys, calcium phosphate, polyaryletherketone (PAEK),polyetheretherketone (PEEK), polyetherketoneketone (PEKK),polyetherketone (PEK), carbon-PEEK composites and PEEK-BaSO4.

Body 12 may be made from materials, such as for example, polyurethane,polyurea, polyether(amide), PEBA, thermoplastic elastomeric olefin,copolyester, and styrenic thermoplastic elastomer, metal alloys withhigh non-ferrous metal content and a low relative proportion of iron,carbon fiber, glass fiber, plastics, ceramics or combinations thereof.

In various embodiments, some or all of body 12 may comprise materialthat is bioresorbable. Examples of suitable biodegradable and/orbioresorbable material include, but is not limited to, poly(alpha-hydroxy acids), poly (lactide-co-glycolide) (PLGA), polylactide(PLA), polyglycolide (PG), polyethylene glycol (PEG), conjugates of poly(alpha-hydroxy acids), polyorthoesters, polyaspirins, polyphosphagenes,collagen, starch, chitosans, gelatin, alginates, dextrans,vinylpyrrolidone, polyvinyl alcohol (PVA), PVA-g-PLGA, PEGT-PBTcopolymer (polyactive), methacrylates, poly (N-isopropylacrylamide),PEO-PPO-PEO (pluronics), PEO-PPO-PAA copolymers, PLGA-PEO-PLGA, orcombinations thereof. In some embodiments, some or all of body 12 maycomprise material that is shape memory material. Examples of suitableshape memory materials include, but are not limited to shape memoryalloys such as nickel-titanium alloys (e.g., nitinol),copper-aluminum-nickel, copper-zinc-aluminum, and iron-manganese-siliconalloys and shape memory polymers such as polyurethanes, polyurethaneswith ionic or mesogenic components, block copolymers comprisingpolyethyleneterephthalate and polyethyleneoxide, block copolymerscontaining polystyrene and polybutadiene, polyesterurethanes withmethylenebis and butanediol, epoxy resins.

In one embodiment, tapered element 22 is movable relative to distal end16 of body 12 between an unexpanded configuration and an expandedconfiguration. In the unexpanded configuration, distal tip 26 protrudesfrom distal end 16 and proximal end 24 remains disposed within distalend 16 of body 12 such that body 12 is insertable between vertebrae.With spacer 10 disposed between lamina L1, L2, body is moved to theexpanded configuration, in which proximal end 24 and distal tip 26 oftapered element 22 protrude from distal end 16 of body 12. In theexpanded configuration, body 12 applies a tensile force on lamina L1,L2.

In one embodiment, as shown in FIG. 2, illustrated is a spinal implant,such as, for example, a spacer 110, similar to spacer 10 described withregard to FIG. 1. Spacer 110 includes a body 112, similar to body 12described herein, extending between a proximal end 114 and a distal end116. As illustrated, proximal end 114 is disposed within distal end 116.In some embodiments, distal end 116 is disposed within proximal end 114.Distal end 116 includes a protrusion, such as, for example, a taperedelement 122, similar to tapered element 22 described herein. Body 112includes an intermediate portion, such as, for example, a spring 128disposed within a cavity 134 defined in ends 114, 116. Spring 128 isengaged to a post 136 extending from distal end 116 and a post 138extending from proximal end 14 to limit the axial displacement of ends114, 116 relative to one another in the expanded configuration. Spring128 resiliently biases ends 114, 116 in opposing directions. Ends 114,116 each include mating parts 130, 132, similar to mating parts 30, 32described herein, that extend into cavity 134 to resist the axialdisplacement of ends 114, 116 relative to one another in the unexpandedconfiguration. To move from the unexpanded configuration to the expandedconfiguration, ends 114, 116 are relatively rotated to disengage matingparts 130, 132 such that spring 128 axially spaces ends 114, 116 andexpands cavity 134.

In one embodiment, as shown in FIG. 2A, illustrated is spacer 110.Spring 128 is engaged to a post 137 extending from distal end 116 toproximal end 114. Post 137 is a central solid post that spring 128 isconfigured to wrap around. Alternatively, in one embodiment, spring 128is disposed within a hollow cylinder which provides rigidity to spacer110. The post 137 transversely extends from the distal end 116 to theproximal end 114 and provides more rigidity, and elasticity as comparedto FIG. 2. A spinal implant that is completely rigid will cause unwantederosion. Therefore, this spinal implant prevents or reduces suchunwanted erosion by providing rigidity as well as longitudinalelasticity.

The spinal implants provided allow for inter-laminar distraction todecompress nerves causing pain (e.g., disc herniation/bulging,hypertrophic ligaments and/or facets, stenosis, facetdegeneration/slippage, etc.). The spinal implants provided, in someembodiments, are implanted in the midline of the posterior spinalcolumn.

Referring to FIG. 3, illustrated is a top view, in part cross section,of an embodiment of a spinal implant, such as, for example, a spacer210, similar to spacer 10 disclosed with regard to FIG. 1. In thisillustrated embodiment, spacer 210 includes a body 212, similar to body12 described herein, including a proximal end 214 and a distal end 216.Distal end 216 includes a tapered element 222, similar to taperedelement 22 described herein. Proximal end 214 includes a bore 218configured for disposal of a driver, such as, for example, animplantation tool 220.

Implantation tool 220 includes, but is not limited to, a driver, wrench,spanner, screwdriver, or other turning tool, and the like that canengage body 212. The implantation tool 220 may be used manually (e.g.,turnable by hand) or by an automatic device (e.g., using a drill, powerdriver, etc.). The implantable tool 220 may be made from materials, suchas for example, polyurethane, polyurea, polyether(amide), PEBA,thermoplastic elastomeric olefin, copolyester, and styrenicthermoplastic elastomer, steel, aluminum, stainless steel, titanium,metal alloys with high non-ferrous metal content and a low relativeproportion of iron, carbon fiber, glass fiber, plastics, ceramics orcombinations thereof. In various embodiments, the implantation tool 220is not biodegradable.

Body 212 includes a jacking member 230 configured for engagement withimplantation tool 220. Proximal and distal ends 214, 216 are movablerelative to one another via jacking member 230 between the unexpandedposition and the expanded position. Jacking member 230 includes a screw232 disposed in coaxial alignment with bore 218. Screw 232 includes ahead configured for mating engagement with a distal end of implantationtool 220 to rotate screw 232 within bore 218. Jacking member 230includes a pair of hinges 234 connected with proximal end 214 and distalend 216 of body 212. Screw 232 is threadedly engaged to a pivot point ofhinges 234 such that the rotation of screw 232 causes hinges 234 to flexoutwardly or inwardly to drive the relative axial movement of ends 214,216. In some embodiments, jacking member 230 is variously configured,such as, for example, as a bell crank, cam, connection rod, crank arm,jack, radius bar, winch, a series of gears or a yoke.

In one embodiment, referring to FIG. 3A, illustrated is a side view of ascrew member 217 of implant body 212, similar to jacking member 230disclosed with regard to FIG. 3. The proximal end 219 and distal end 215of the implant body are connected by a screw member 217, where rotationof the proximal end 219 and/or distal end 215 of the implant body willallow the proximal and distal end of the implant body to move closertogether if turned in one direction, or move further apart if rotated inan opposite direction. In this way, the length of the implant body canbe adjusted by the rotation. Screw member 217 includes a proximal endand a distal end with an intermediate portion comprising a screw thread221 that engages reciprocating internal screw threading (not shown) inthe proximal and/or distal end.

FIGS. 4 and 5 illustrate a method for treating a spine disorder, suchas, for example, spinal stenosis pain. A medical practitioner obtainsaccess to a surgical site including vertebrae V in any appropriatemanner, such as through incision and retraction of tissues. In someembodiments, spacer 10 can be used in any existing surgical method ortechnique including open surgery, mini-open surgery, minimally invasivesurgery and percutaneous surgical implantation, whereby vertebrae V isaccessed through a mini-incision, or sleeve that provides a protectedpassageway to the area. Once access to the surgical site is obtained,the particular surgical procedure can be performed for treating thespine disorder.

An incision is made in a body of a patient and a cutting instrument (notshown) creates a surgical pathway along, in some embodiments, asubstantially posterior approach for implantation of components ofspacer 10 within the patient body. Spacer 10 is oriented in theunexpanded position, as shown in FIG. 4, with mating parts 28, 30 inengagement. Guidewire 20 is inserted into lamina L2. A drill (not shown)is guided along guidewire 20 into contact with lamina L2 and actuated toform a cavity C in lamina L2 sized and dimensioned for disposal oftapered element 22 while allowing for some rotational movement withincavity C. The drill is removed from the surgical site and spacer 10 ispositioned over guidewire 20 and axially guided along guidewire 20toward lamina L2 to dispose tapered element 22 in cavity C. Guidewire 20is removed from the surgical site. Spacer 10 is rotated relative tolamina L2 about tapered element 22 guiding notch 18 along a spinousprocess SP1. Spacer 10 is rotated until lamina L1 is disposed in notch18 such that ends 14, 16 are disposed in an interlaminar space S betweenlamina L1, L2. Ends 14, 16 are relatively rotated to disengage matingparts 30, 32 such that intermediate portion 28 axially spaces ends 14,16 and anchors distal end 16 with lamina L2 and proximal end 14 withlamina L1 to alleviate pressure on nerves and the spinal cord. Thespinal implant device provided allows notch 18 to engage the lamina L1and the lamina L1 is seated just above notch 18 as shown in FIG. 5.

FIG. 6 illustrates a method for treating a spine disorder, such as, forexample, spinal stenosis pain, similar to the method described withregard to FIGS. 4 and 5. In this embodiment, spacer 210 is disposedbetween lamina L1, L2 in the interlaminar space S. With body 212 locatedbetween lamina L1, L2, implantation tool 220 is inserted within bore 218into engagement with screw 232 and rotated, in the direction shown byarrow A in FIG. 6, flexing hinges 234 inwardly. The inward flexion ofhinges 234 axially spaces ends 214, 216 and anchors proximal end 214with lamina L1 and distal end 216 with lamina L2. In some embodiments,implantation tool 220 is used to wedge spacer 20 between lamina L1, L2.

Radiographic markers can be included on spacer 10 to permit the user toaccurately position spacer 10 into the desired site of the patient.These radiographic markers will also permit the user to track movementof spacer 10 at the site over time. In this embodiment, the user mayaccurately position spacer 10 in the site using any of the numerousdiagnostic imaging procedures. Such diagnostic imaging proceduresinclude, for example, X-ray imaging or fluoroscopy. Examples of suchradiographic markers include, but are not limited to, barium, calciumphosphate, and/or metal beads. For example, the radiographic marker canbe ring-shaped or dispersed as small pellets throughout spacer 10.

In various embodiments, spacer 10 may include a transparent ortranslucent portion that can be visualizable by ultrasound, fluoroscopy,x-ray, or other imaging techniques. In such embodiments, the transparentor translucent portion may include a radiopaque material or ultrasoundresponsive topography that increases the contrast of spacer 10 relativeto the absence of the material or topography.

Therapeutic Agents

In various embodiments, spacer 10 comprises a drug depot attached orcoated thereto. A drug depot comprises a physical structure tofacilitate implantation and retention in a desired site (e.g., a discspace, a spinal canal, a tissue of the patient, etc.) or adjacent to thedesired site. The drug depot also comprises the drug. The term “drug” asused herein is generally meant to refer to any substance that alters thephysiology of a patient. The term “drug” may be used interchangeablyherein with the terms “therapeutic agent”, “therapeutically effectiveamount”, and “active pharmaceutical ingredient”. It will be understoodthat a “drug” formulation may include more than one therapeutic agent,wherein exemplary combinations of therapeutic agents include acombination of two or more drugs. The drug provides a concentrationgradient of the therapeutic agent for delivery to the site. In variousembodiments, the drug depot provides an optimal drug concentrationgradient of the therapeutic agent at a distance of up to about 1 cm toabout 5 cm from the implant site.

Examples of drugs suitable for use in the drug depot, include, but arenot limited to an anti-inflammatory agent, analgesic agent, orosteoinductive growth factor or a combination thereof. Anti-inflammatoryagents include, but are not limited to, salicylates, diflunisal,indomethacin, ibuprofen, naproxen, tolmetin, ketorolac, diclofenac,ketoprofen, fenamates (mefenamic acid, meclofenamic acid), enolic acids(piroxicam, meloxicam), nabumetone, celecoxib, etodolac, nimesulide,apazone, gold, sulindac or tepoxalin; antioxidants, such asdithiocarbamate, and other compounds such assulfasalazine[2-hydroxy-5-[-4-[C2-pyridinylamino)sulfonyl]azo]benzoicacid], steroids, such as fluocinolone, cortisol, cortisone,hydrocortisone, fludrocortisone, prednisone, prednisolone,methylprednisolone, triamcinolone, betamethasone, dexamethasone,beclomethasone, fluticasone or a combination thereof.

Suitable osteoinductive factors include, but are not limited to, a bonemorphogenetic protein, a growth differentiation factor, a LIMmineralization protein or a combination thereof.

Suitable analgesic agents include, but are not limited to,acetaminophen, lidocaine, bupivicaine, opioid analgesics such asbuprenorphine, butorphanol, dextromoramide, dezocine,dextropropoxyphene, diamorphine, fentanyl, alfentanil, sufentanil,hydrocodone, hydromorphone, ketobemidone, levomethadyl, mepiridine,methadone, morphine, nalbuphine, opium, oxycodone, papaveretum,pentazocine, pethidine, phenoperidine, piritramide, dextropropoxyphene,remifentanil, tilidine, tramadol, codeine, dihydrocodeine, meptazinol,dezocine, eptazocine, flupirtine or a combination thereof. Analgesicsalso include agents with analgesic properties, such as for example,amitriptyline, carbamazepine, gabapentin, pregabalin, clonidine, or acombination thereof.

A “depot” includes but is not limited to capsules, microspheres,particles, gels, coating, matrices, wafers, pellets or otherpharmaceutical delivery compositions. A depot may comprise a biopolymerthat is either biodegradable or non-degradable. A depot may comprise abiopolymer that may provide for immediate release or sustained releaseor controlled release. Examples of suitable sustained releasebiopolymers include but are not limited to poly (alpha-hydroxy acids),poly (lactide-co-glycolide) (PLGA), polylactide (PLA), polyglycolide(PG), polyethylene glycol (PEG) conjugates of poly (alpha-hydroxyacids), polyorthoesters, polyaspirins, polyphosphagenes, collagen,starch, chitosans, gelatin, alginates, dextrans, vinylpyrrolidone,polyvinyl alcohol (PVA), PVA-g-PLGA, PEGT-PBT copolymer (polyactive),methacrylates, poly (N-isopropylacrylamide), PEO-PPO-PEO (pluronics),PEO-PPO-PAA copolymers, PLGA-PEO-PLGA, or combinations thereof.

The drug depot may be any shape, for example, bullet shaped, spherical,substantially spherical, flaked, rod shaped, square, oval, etc. The drugdepot comprises a body that is made from a biodegradable material. Inalternative embodiments, the body may be made from a non-biodegradablematerial. A non-biodegradable body could be a porous hollow chamberfilled with the therapeutic agent alone or incorporated into adegradable polymer. It may be desirable to make the body non-degradableto be able to retrieve it after it has released or exhausted itscontents. Or the non-biodegradable body could be a small pump thatpushes the contents out pores, port(s), or a cannula. The body of thedrug depot may be solid and a therapeutic agent may be dispersedthroughout the material that forms the body. The dispersal of thetherapeutic agent may be even throughout the body or in various parts ofthe body in layers (e.g., one third, two thirds, three fourths, etc.).

As the biodegradable material of the body degrades within the tissue,the therapeutic agent is released. Suitable sustained release materialsmay be used in the drug depot to carry the one or more therapeuticagents and control the release of the therapeutic agent(s). For example,microspheres may be used to encapsulate the therapeutic agent; thetherapeutic agent-containing microspheres are then dispersed through thebody of the drug depot.

The drug depot can be designed for gradient variations inbiodegradability to hold the depot in place while the secondary materialreleases its contents. The drug depot may have a width from about 1 mmto about 6 mm and a length from about 5 mm to about 20 mm. Selection ofsuitable lengths and widths for the drug depot will depend upon thetargeted implant site; dosage required and is well within the abilitiesof those having ordinary skill in the art.

In various embodiments, procedures for making the drug depot include,but are not limited to, extrusion-spheroidization, for spherical depotswhere the active pharmaceutical ingredient (API) and any inactiveingredients (excipients, binders, etc.) are pre-mixed, then wetted withwater, in a high shear mixer to form a damp mass. The damp mass is thentransferred into an extruder where it is forced through a screen or dieplate, where it forms an essentially solid, cylindrical extrudate ofuniform shape and size. The size of the opening in the screen or diedictates the resultant drug depot size. The extrudate is fed onto arotating disk, which may be smooth or may contain a grid (waffled,grooved, etc.) and the extrudate breaks into small cylinders, which intime are rounded into spherically shaped solids. Subsequently, the drugdepots are dried to the desired residual moisture content, typically ina fluid bed dryer. Any oversized or undersized product is removed bysieving, and the resulting drug depots have a narrow size distribution.

In various embodiments, the API is layered on the solid body of the drugdepot by solution or suspension layering or powder layering techniques.In solution or suspension layering, an API and any inactive ingredients(excipients, binders, etc.) are suspended or dissolved in water or anorganic solvent. The resulting liquid is sprayed onto the outside of abody, which may include, for example, non-pareil sugar seed (sugarsphere), microcrystalline cellulose depots and the like, to make thedepot having the desired potency. Solution or suspension layering may beconducted using a wide variety of process techniques, for example, byfluidized bed, Wurster bottom spray techniques, or the like. When thedesired potency has been achieved, the depots are dried to the desiredresidual moisture content. Any oversized or undersized product may beremoved by sieving, and the resulting depots are narrow in sizedistribution.

Powder layering may also be used to make the drug depot. Powder layeringinvolves the application of a dry powder to the body material. Thepowder may contain the drug, or may include excipients such as a binder,flow aid, inert filler, and the like. In the powder layering technique apharmaceutically acceptable liquid, which may be water, organic solvent,with or without a binder and/or excipients, is applied to the bodymaterial while applying the dry powder until the desired potency isachieved. When the desired potency has been achieved, the drug depotsmay be seal coated to improve their strength, and are then dried to thedesired moisture content. Any oversized or undersized product is removedby sieving, and the resulting drug depots are narrow in sizedistribution.

In one embodiment, the drug depot is made using a body of biodegradablematerial, such as, for example, polyglactin, polylactone, polylactide,etc. The body is then coated with a thin layer of the API, such as ananti-inflammatory agent, analgesic agent, etc. by solution, suspension,or powdered layering until the desired potency is achieved.

In various embodiments, the drug depot can be different sizes, forexample, from about 1 mm to 5 mm and have a diameter of from about 0.01to about 2 mm. The layer or layers will each have a layer thickness offrom about 0.005 to 1.0 mm, such as, for example, from 0.05 to 0.75 mm.

Spacer 10 and/or drug depot may be disposable and sterilizable. Invarious embodiments, one or more components of spacer 10 are sterilizedby radiation in a terminal sterilization step in the final packaging.Terminal sterilization of a product provides greater assurance ofsterility than from processes such as an aseptic process, which requireindividual product components to be sterilized separately and the finalpackage assembled in a sterile environment.

Typically, in various embodiments, gamma radiation is used in theterminal sterilization step, which involves utilizing ionizing energyfrom gamma rays that penetrates deeply in spacer 10. Gamma rays arehighly effective in killing microorganisms, they leave no residues norhave sufficient energy to impart radioactivity to spacer 10. Gamma rayscan be employed when spacer 10 is in the package and gamma sterilizationdoes not require high pressures or vacuum conditions, thus, packageseals and other components are not stressed. In addition, gammaradiation eliminates the need for permeable packaging materials.

In various embodiments, electron beam (e-beam) radiation may be used tosterilize one or more components of spacer 10. E-beam radiationcomprises a form of ionizing energy, which is generally characterized bylow penetration and high-dose rates. E-beam irradiation is similar togamma processing in that it alters various chemical and molecular bondson contact, including the reproductive cells of microorganisms. Beamsproduced for e-beam sterilization are concentrated, highly-chargedstreams of electrons generated by the acceleration and conversion ofelectricity. E-beam sterilization may be used, for example, when thedrug depot includes a gelatin capsule.

Other methods may also be used to sterilize one or more components ofspacer 10, including, but not limited to, gas sterilization, such as,for example, with ethylene oxide or steam sterilization.

In various embodiments, a kit is provided which may include additionalparts along with spacer 10 combined together. The kit may include body12 in a first compartment. A second compartment may include the drugdepot, and the implantation tool, guidewire, and any other instrumentsneeded for the implant. A third compartment may include gloves, drapes,wound dressings and other procedural supplies for maintaining sterilityduring the implanting process, as well as an instruction booklet. Afourth compartment may include cannulas and/or needles. Each tool may beseparately packaged in a plastic pouch that is radiation sterilized. Acover of the kit may include illustrations of the implanting procedureand a clear plastic cover may be placed over the compartments tomaintain sterility.

Spacer 10 may be used to treat a disease or condition such as forexample, rheumatoid arthritis, osteoarthritis, sciatica, carpal tunnelsyndrome, lower back pain, lower extremity pain, upper extremity pain,cancer, tissue pain and pain associated with injury or repair ofcervical, thoracic, and/or lumbar vertebrae or intervertebral discs,rotator cuff, articular joint, TMJ, tendons, ligaments, muscles, and thelike.

In various embodiments, spacer 10 and the drug depot are used to treatpain, or other diseases or conditions of the patient. Pain includesacute pain and neuropathic pain associated with spinal stenosis. Acutepain refers to pain experienced when tissue is being damaged or isdamaged (e.g., injury, infection, etc.). As contrasted to acute pain,neuropathic pain serves no beneficial purpose. Neuropathic pain resultswhen pain associated with an injury or infection continues in an areaonce the injury or infection has resolved. Sciatica provides an exampleof pain that can transition from acute to neuropathic pain. Sciaticarefers to pain associated with the sciatic nerve which runs from thelower part of the spinal cord (the lumbar region), down the back of theleg and to the foot. Sciatica generally begins with a herniated disc.The herniated disc itself leads to local immune system activation. Theherniated disc also may damage the nerve root by pinching or compressingit, leading to additional immune system activation in the area.

In various embodiments, once spacer 10 is anchored at the implant siteand the drug is released from the drug depot over a period of time(e.g., days, months, years, etc.) and exhausted, the user (e.g.,surgeon, physician, nurse, etc.) may remove the exhausted drug depotfrom spacer 10 without removing spacer 10 itself.

For example, the user can clip or cut the suture line holding the drugdepot and replace it with another new drug depot. In this way, accurateand precise implantation of the replacement drug depot with minimalphysical and psychological trauma to the patient result. Now successfultreatment plans can be continued by merely replacing exhausted drugdepots with new drug depots position at one or more treatment sites. Invarious embodiments, the drug depot is removed without removing spacer10.

Radiographic markers can be included on spacer 10 and/or drug depot topermit the user to accurately position the depot into the site of thepatient. These radiographic markers will also permit the user to trackmovement and degradation of the depot at the site over time. In thisembodiment, the user may accurately position the depot in the site usingany of the numerous diagnostic imaging procedures. Such diagnosticimaging procedures include, for example, X-ray imaging or fluoroscopy.When a subsequent image is taken of the treatment site, the user now canlook for the degraded or exhausted drug depot and remove it and replaceit with a new drug depot having fresh drug at the same or differentdosage by, for example, threading a new suture or wire having the drugdepot disposed on it through the hole and tying it to spacer 10.

The dosage administered, to an individual as single or multiple doseswill vary depending upon a variety of factors, including the agent'spharmacokinetic properties, patient conditions and characteristics (sex,age, body weight, health, size, etc.), extent of symptoms, concurrenttreatments, frequency of treatment and the effect desired. These factorscan readily be determined by those of ordinary skill in the art.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to various embodimentsdescribed herein without departing from the spirit or scope of theteachings herein. Thus, it is intended that various embodiments coverother modifications and variations of various embodiments within thescope of the present teachings.

What is claimed is:
 1. A spinal implant, comprising: a body extendingbetween a proximal end and a distal end, the body including anexpandable intermediate portion disposed between the proximal end andthe distal end, the body comprising a shape memory material, theproximal end defining a notch configured for disposal in a firstvertebra, and comprising a first mating part, the distal end comprisinga protrusion configured for disposal in a second vertebra, and a secondmating part, wherein the proximal and distal ends are movable relativeto one another between an unexpanded position in which the spinalimplant is configured to be inserted between lamina and an expandedposition in which the spinal implant is configured to be disposedbetween the lamina, and the first mating part is configured to engagethe second mating part in the unexpanded position, and the spinalimplant is configured to move in the expanded position when the proximalend and the distal end are rotated relatively to one another todisengage the first mating part with the second mating part.
 2. A spinalimplant as recited in claim 1, wherein the intermediate portion includesa biasing member, the biasing member resiliently biasing the body to theexpanded position.
 3. A spinal implant as recited in claim 1, whereinthe protrusion includes a roughened outer surface.
 4. A spinal implantas recited in claim 1, wherein the protrusion has a rounded distal tip.5. A spinal implant as recited in claim 1, wherein the protrusion has acone-shaped configuration.
 6. A spinal implant as recited in claim 1,wherein the protrusion is movable relative to the distal end.
 7. Aspinal implant as recited in claim 1, wherein the protrusion has apointed distal tip configured for penetrating engagement with spinaltissue.
 8. A spinal implant as recited in claim 1, wherein the firstvertebra includes an inferior lamina and the second vertebra includes asuperior lamina.
 9. A spinal implant as recited in claim 1, wherein thebody further comprises at least one of stainless steel alloys,commercially pure titanium, titanium alloys, Grade 5 titanium,cobalt-chrome alloys, stainless steel alloys, calcium phosphate,polyaryletherketone (PAEK), polyetheretherketone (PEEK),polyetherketoneketone (PEKK), polyetherketone (PEK), carbon-PEEKcomposites and PEEK-BaSO4.
 10. A spinal implant as recited in claim 1,wherein the body is cannulated along its length.
 11. A spinal implant asrecited in claim 1, wherein the shape memory material comprises shapememory polymers such as polyurethanes, polyurethanes with ionic ormesogenic components, block copolymers comprisingpolyethyleneterephthalate and polyethyleneoxide, block copolymerscontaining polystyrene and polybutadiene, polyesterurethanes withmethylenebis and butanediol, and epoxy resins.
 12. A spinal implant asrecited in claim 1, wherein the spinal implant is bullet shaped.
 13. Aspinal implant as recited in claim 1, wherein each mating part includesa hook.
 14. A spinal implant, comprising: a body extending between aproximal end and a distal end, the proximal end comprising a firstmating part, and the proximal end is configured for disposal in a firstvertebra, the distal end comprising a second mating part, and the distalend is configured for disposal in a second vertebra, wherein theproximal and distal ends are movable relative to one another between anunexpanded position in which the spinal implant is configured to beinserted between lamina and an expanded position in which the spinalimplant is configured to be disposed between the lamina so as to allowelasticity during motion, and the first mating part is configured toengage the second mating part in the unexpanded position, and the spinalimplant is configured to move in the expanded position when the proximalend and the distal end are rotated relatively to one another todisengage the first mating part with the second mating part, the spinalimplant being bullet shaped, and the body comprising a shape memorymaterial.